This proposal is comprised of two parts. The first part proposes a study of specific enzyme synthesis and expression during the cell cycle in synchronous plasmodia of the slime mold, Physarum polycephalum. The catalytic expression of a specific enzyme activity during the cell cycle generally demonstrates one of three basic patterns, namely: a peak, a step, or a continuous function. This application proposes to study six enzymes which demonstrate these activity patterns. They include: uridine 5' -diphospholglucose pyrophosphorylase, beta-N-acetylhexosaminidase, uridine 5' - diphosphoglucose 4-epimerase, NAD ion -pyrophosphorylase, and thymidine kinase. Enzyme activity patterns during the cell cycle will be correlated with immunologic and radioisotope techniques as adjuncts to isolation and purification of each enzyme. The second part of this application is an attempt to corroborate our proposal that the simple, aliphatic polyamines (putrescine, spermidine, and spermine) are determinants of the quality and quantity of nuclear non-histone acidic protein phosphorylations in isolated nuclei from P. polycephalum, and thus are regulatory factors in genetic transcription. Four non-histone acidic proteins, which are highly phosphorylated in the presence of the polyamines, will be purified. Their capacity to modulate in vitro transcription of homologous DNA, chromatin, and ribosomal DNA will be investigated. These proteins will also be characterized with respect to their putative cyclic adenosine 3', 5'-monophosphate (cAMP)-binding capacity and phosphoglycoprotein properties. On the basis of preliminary work, it is also proposed that the polyamines and cAMP are components of a tightly controlled, negative-feedback regulatory loop in which each functions as a major regulatory factor in controlling the synthesis of the other. This proposal will be tested by a correlative approach through the use of metabolic inhibitors of polyamine biosynthesis and cAMP synthesis. A final investigation will attempt to isolate polyamine mutants from haploid amoebae (strain CLd) of an apogamic strain of P. polycephalum. Plasmodial mutants derived from these amoebae will be used for identifying cell cycle altered by polyamine deprivation.